Stephen Chu-Sung Hu1, I-Ta Lee2, Ming-Hong Yen3, Chun-Ching Lin3, Chiang-Wen Lee4, Feng-Lin Yen5. 1. Department of Dermatology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Dermatology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. 2. School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan. 3. School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan. 4. Division of Basic Medical Sciences, Department of Nursing, Chang Gung Institute of Technology and Chronic Diseases and Health Promotion Research Center, Chiayi, Taiwan; Research Center for Industry of Human Ecology, Chang Gung University of Science and Technology, Kweishan, Taoyuan, Taiwan. Electronic address: cwlee@gw.cgust.edu.tw. 5. Department of Fragrance and Cosmetic Science, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan; Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan. Electronic address: flyen@kmu.edu.tw.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Bupleurum chinense is a traditional Chinese medicinal herb which has been used to treat various inflammatory and infectious diseases, while Bupleurum kaoi is an endemic plant in Taiwan. We determined whether B. chinense and B. kaoi and their biologically active saikosaponin compounds possess anti-melanoma activity. In addition, we developed a novel saikosaponin-d nanoparticle system to improve its solubility, and evaluated its antiproliferative effects and molecular mechanisms in melanoma cells. MATERIALS AND METHODS: Ethanolic extracts from B. chinense and B. kaoi were prepared, and their saikosaponin contents were determined by high performance liquid chromatography analysis. Saikosaponin-d nanoparticles were synthesized, and their physicochemical properties were evaluated by particle size analyzer, transmission electron microscopy, differential scanning calorimetry, X-ray diffractometry, and Fourier transform infrared spectroscopy. Human A375.S2 melanoma cells were cultured, and cell viability determined by the MTT assay. Apoptosis was evaluated by determination of mitochondrial membrane potential, and signal transduction pathways investigated by Western blotting. RESULTS: Ethanolic extracts from B. kaoi showed more potent antiproliferative effect on human A375.S2 melanoma cells compared to B. chinense. The saikosaponin-a, -c and -d contents were higher in B. kaoi compared to B. chinense. Saikosaponin-d was the most potent compound in terms of anti-melanoma activity, and saikosaponin-d nanoparticles exhibited increased water solubility due to lowered particle size, amorphous transformation and intermolecular hydrogen bond formation with the excipient. Furthermore, saikosaponin-d nanoparticles showed enhanced antiproliferative activity against melanoma cells, and induced apoptosis through the mitochondrial pathway. The anti-melanoma activity was mediated by phosphorylation of JNK and p38, phosphorylation of p53, increased level of cytochrome c, and activation of caspase 9. CONCLUSIONS: B. kaoi contains higher saikosaponin content and shows greater anti-melanoma activity than B. chinense. Saikosaponin-d nanoparticles have improved solubility, and may have potential use in the future as a form of treatment for melanoma.
ETHNOPHARMACOLOGICAL RELEVANCE: Bupleurum chinense is a traditional Chinese medicinal herb which has been used to treat various inflammatory and infectious diseases, while Bupleurum kaoi is an endemic plant in Taiwan. We determined whether B. chinense and B. kaoi and their biologically active saikosaponin compounds possess anti-melanoma activity. In addition, we developed a novel saikosaponin-d nanoparticle system to improve its solubility, and evaluated its antiproliferative effects and molecular mechanisms in melanoma cells. MATERIALS AND METHODS: Ethanolic extracts from B. chinense and B. kaoi were prepared, and their saikosaponin contents were determined by high performance liquid chromatography analysis. Saikosaponin-d nanoparticles were synthesized, and their physicochemical properties were evaluated by particle size analyzer, transmission electron microscopy, differential scanning calorimetry, X-ray diffractometry, and Fourier transform infrared spectroscopy. Human A375.S2 melanoma cells were cultured, and cell viability determined by the MTT assay. Apoptosis was evaluated by determination of mitochondrial membrane potential, and signal transduction pathways investigated by Western blotting. RESULTS: Ethanolic extracts from B. kaoi showed more potent antiproliferative effect on human A375.S2 melanoma cells compared to B. chinense. The saikosaponin-a, -c and -d contents were higher in B. kaoi compared to B. chinense. Saikosaponin-d was the most potent compound in terms of anti-melanoma activity, and saikosaponin-d nanoparticles exhibited increased water solubility due to lowered particle size, amorphous transformation and intermolecular hydrogen bond formation with the excipient. Furthermore, saikosaponin-d nanoparticles showed enhanced antiproliferative activity against melanoma cells, and induced apoptosis through the mitochondrial pathway. The anti-melanoma activity was mediated by phosphorylation of JNK and p38, phosphorylation of p53, increased level of cytochrome c, and activation of caspase 9. CONCLUSIONS:B. kaoi contains higher saikosaponin content and shows greater anti-melanoma activity than B. chinense. Saikosaponin-d nanoparticles have improved solubility, and may have potential use in the future as a form of treatment for melanoma.